textproduct: Quad Cities

KEY MESSAGES

- Shower and storm chances (30-70%) return Friday for areas mainly north of I-80 and some of the storms may become strong to severe.

- A stretch of quiet and mostly dry weather will be seen this weekend into early next week, with seasonal temperatures.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 1225 PM CDT Thu Aug 20 2026

Surface high pressure will remain in place through the rest of today which should lead to a quiet weather day. Temperatures once again will remain near average, with afternoon highs reaching the upper 70s to low 80s across the region. The winds the rest of the day will be fairly light as well, which will lead to a very pleasant afternoon across the forecast area! Mostly sunny skies are forecast for today, but that will change as we go into tonight as positive H700 theta-e advection moves in out ahead of a very weak shortwave trough. Even though there will be lift provided by the shortwave, confidence in any light rain showers developing tonight is very low as there is quite a bit of dry air below 10k ft agl tonight.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 1225 PM CDT Thu Aug 20 2026

The potential for rain showers and thunderstorms will increase on Friday, especially during the afternoon into the evening time frame. Another shortwave will move southeast from the Northern High Plains towards the Midwest during the day. This wave will usher in a cold front which will move over the forecast area on Friday. Given the low confidence in any showers during the morning, plenty of instability should be able to build during the day as temperatures rise into the 80s and dew points quickly climb. Forecast soundings continue to depict MLCAPE values rising up to 3000 J/kg out ahead of the front tomorrow afternoon. Deep layer shear is not all that impressive out ahead of this system, with model guidance showing values around 30 kts, but they are sufficient enough to at least attempt to build organized convection along the front. Any storms that are able to form in this environment will have the potential to become strong to severe, with the most likely hazard being damaging wind gusts as a linear complex may develop along the front. If any storms can remain discrete, some large hail cannot be ruled out. Storms should be relatively quick moving along the front and should be out of the area by late evening.

After that system departs to the east, the region looks to be under mainly northwest flow for much of the remainder of this forecast period. This is in part to troughing over the northeastern US with a ridge of high pressure building over the Rockies into the Great Plains. Very mild conditions are likely this weekend through the start of the next work week with afternoon highs in the 70s to low 80s. Upper level high pressure over the southern High Plains may retreat back west during the middle of next week which would increase the potential for moisture return over the Midwest. However, that is still nearly a week out so any slight change in the pattern could occur so confidence is low at this time.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 633 PM CDT Thu Aug 20 2026

VFR conditions are expected to continue through much of the TAF period. High pressure and dry low-level air should help maintain high ceilings tonight, along with light and variable winds. Eventually, winds will turn from the southwest around sunrise Friday and strengthen to around 10 knots.

The main focus for this TAF set will be on increasing chances of showers/storms (40-70%) Friday afternoon. There may be some light showers prior to this time during the late morning at DBQ, but impacts from this should be pretty minimal. Any storms that develop Friday afternoon could become severe, packing locally strong wind gusts and heavy rainfall, leading to reduced visibility. At this time, confidence in the exact coverage/location of storms is very low. However, areas most likely to see these storms include DBQ and MLI (although MLI might see storms closer to 00z Saturday/7 PM Friday).

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.